Hack-charging on a generator

Dino Saver · Aug 23, 2012

If my ICE runs out of gas, I can use a gas can to add emergency fuel. What happens if the public charger I'm counting on is out of service or I fail to notice my charge is low and I'm too far from anyone's exterior power outlet when I shut down? Can I hack-charge my Model S? Specifically, can I clip on a charger/starter or a standard 12V somewhere and add emergency power to the battery and limp home? I'm asking in part b/c I have a poor man's solar-powered cabin 100 miles away (and 5000ft up). I'd love to connect the S into a solar panel and inverter for a little extra range so I don't need to stop on the way there or back for an hour. Please don't suggest I get the 85. I've already somehow talked myself into the 60.

And while I'm in survivalist mode, what happens if my Model S blows a tire? I have a spare in the trunk of my ICE. Aside from space, is there any reason not to carry a spare in one's S? I don't play golf or do the food shopping. I'm not sure what I need all that space for besides a spare.

Thanks for your comments.

Doug_G · Aug 23, 2012

No.

You're going to need a steady and stable 1.3 kW minimum to charge the Model S. That's what you get from a 110V 15A circuit

If the Roadster is any indication you can't even use a generator to charge it. The power isn't stable or clean enough and the car will refuse to charge.

widodh · Aug 23, 2012

You won't be able to charge the Model S on 12V, you will need at least 110V

So if you have a solar array which can put out 110V with 4A you would be able to charge the Model S very, very slowly.

When the battery falls below X percent the Model S will refuse to drive and you won't be able to do anything about that except charging it.

You can always place a small generator in your cabin with a couple of gallons of fuel, that way you will be able to emergency charge the Model S.

Doug_G said:
No.

You're going to need a steady and stable 13 kW minimum to charge the Model S. That's what you get from a 110V 15A circuit

If the Roadster is any indication you can't even use a generator to charge it. The power isn't stable or clean enough and the car will refuse to charge.

I don't agree fully on that.

The website says:

10 kW capable on-board charger with the following input compatibility: 85-265 V, 45-65 Hz, 1-40 A

So with the right EVSE in between you would be able to charge on 1 or 2A.

I've charged the Roadster on a generator a couple of times, no problems.

Doug_G · Aug 23, 2012

I'm told Transport Canada tried charging their Roadster on seven different generators, and none of them worked. I know another owner who tried a generator with no luck.

I'd be very surprised if you could reduce the draw down to a couple of amps. You certainly can't in the Roadster.

Vger · Aug 23, 2012

I think Doug_G meant 1.3 kW.

I think you would be best served by locating two or three EVSE's or RV parks or places with standard external 120V outlets en route, so you have some options. The only times I have come close to a problem was when I cut charging short to try to make a time deadline. Do NOT be tempted to do that! Take your time, plan a little, and you will be fine.

jkirkebo · Aug 23, 2012

Doug_G said:
I'm told Transport Canada tried charging their Roadster on seven different generators, and none of them worked. I know another owner who tried a generator with no luck.

My Leaf charges fine at 16A on my Honda EU65iS generator at least. But I don't think any generators provide cleaner power than the Honda EU-series so it might not mean much.

jerry33 · Aug 23, 2012

I believe it depends on the kind of power the generator outputs. If it's true sine wave power then there should be no problem, but modified or square sine waves don't cut it. Of course, it's cheaper to make a modified sine wave and even cheaper to make a square wave so those are the kind of generator most folks purchase.

Doug_G · Aug 23, 2012

Vger said:
I think Doug_G meant 1.3 kW.

Typo fixed, thanks.

Majerus · Aug 23, 2012

I wonder if a whole home generator like http://www.generac.com/Residential/Guardian/Products/Guardian_Series_17_kW/ Would charge the car.

FlasherZ · Aug 23, 2012

jerry33 said:
I believe it depends on the kind of power the generator outputs. If it's true sine wave power then there should be no problem, but modified or square sine waves don't cut it. Of course, it's cheaper to make a modified sine wave and even cheaper to make a square wave so those are the kind of generator most folks purchase.

Actually, I think you're referring to inverter-driven electronics. All engine-driven generators produce true sine waves due to the spinning turbine.

However, I have had UPS's refuse to charge on cheap generators because engine speed variations don't hold a true 60 Hz.

Dborn · Aug 23, 2012

If you want to use solar panels, then you would need a decent sized array, say 3 kWh, and then put that into a battery bank. Size of the bank can be for a full charge, (will charge up while you are away), and then the output from the batteries can be fed through a true sine wave inverter of decent quality which would give you 240volts if you so desire. Plug your car in and you are good to go. Also, the problems of clean power from a generator can be solved with an appropriate modulator.120 to 120volt or even 220 volt which charge you up faster. Any solution is not going to be cheap.....

cinergi · Aug 23, 2012

FlasherZ said:
Actually, I think you're referring to inverter-driven electronics. All engine-driven generators produce true sine waves due to the spinning turbine.

However, I have had UPS's refuse to charge on cheap generators because engine speed variations don't hold a true 60 Hz.

Portable generators don't. There's a link to a very informative article somewhere on these forums that I can't find which I remember reading a while ago. Very eye-opening. The alternators they use produce different outputs and even the really good ones still don't come anywhere close to the grid. The generators that are coupled with inverters typically produce a much better wave form.

Wish I could find it -- maybe someone else knows what I'm talking about it and can search for it. "Generator" produces 13 pages of results :smile:

Edit: I should clarify it has a lot to do with the waveform deformation that happens under various types of loads. Resistive loads are quite different than the load from a motor or an electronic device, for example.

hcsharp · Aug 23, 2012

widodh said:
...
I've charged the Roadster on a generator a couple of times, no problems.

Wow what kind of generator was it? I've tried a couple times with no joy.

cinergi said:
Portable generators don't. There's a link to a very informative article somewhere on these forums that I can't find which I remember reading a while ago. Very eye-opening. The alternators they use produce different outputs and even the really good ones still don't come anywhere close to the grid. The generators that are coupled with inverters typically produce a much better wave form.

Wish I could find it -- maybe someone else knows what I'm talking about it and can search for it. "Generator" produces 13 pages of results :smile:

Edit: I should clarify it has a lot to do with the waveform deformation that happens under various types of loads. Resistive loads are quite different than the load from a motor or an electronic device, for example.

I have charged with no problems off of an inverter that produced a true sine wave. So it's possible to do this with a solar array and battery storage. I'm not sure how you know which inverters work, and which don't. A lot of them advertise "true sine wave" but it's not all that "true" or "clean".

One time I charged off of a Prius! The owner was showing off some equipment he was selling that taps directly into the Prius battery. The inverter was about the size of a desktop computer and capable of producing 115v 20A. I told him it wouldn't work but I plugged in and charged for a couple hours. I had a volt meter and the voltage was very stable at 115.

FlasherZ · Aug 23, 2012

Ah yes, I recall reading the same thing in a prior post as well, although if I recall correctly, it was only in the case where a battery charger or UPS was the only load on the generator, and that a constant, resistive load of 2-5A would suppress most of the distortion (500-1000W of incandescent lights or a small heater).

What I typed was still true, though, in that the alternators found in generator sets do generate sine waves and do not create stepped/modified or square waves.

cinergi · Aug 23, 2012

Found the article!
ScreenLight & Grip's E-Newsletter

It's a HUGE article .. but scroll to (use browser's find feature) "Portable Generator Types" to see some of what I was talking about ...

widodh · Aug 24, 2012

hcsharp said:
Wow what kind of generator was it? I've tried a couple times with no joy.

From a dutch supplier (Bredenoord), it was a 40kW diesel generator.

Charged with 16 and 32A off that generator.

jkirkebo · Aug 24, 2012

cinergi said:
Portable generators don't. There's a link to a very informative article somewhere on these forums that I can't find which I remember reading a while ago. Very eye-opening. The alternators they use produce different outputs and even the really good ones still don't come anywhere close to the grid. The generators that are coupled with inverters typically produce a much better wave form.

*Most* portable generators don't. The Honda EU20i is very portable and will produce cleaner power than you get from the grid. Hz output is not tied to engine speed at all. The generator output is rectified and then fed to an inverter which makes perfect 60Hz (or 50Hz in Europe) sine wave. My EU65iS also does this, but it's not what you'll call portable. Movable, maybe...

MikeK · Aug 24, 2012

This has been really informative. I was planning to buy a back-up generator for the house. Now I know to look for a Honda inverter generator!

mknox · Aug 24, 2012

Dino Saver said:
If my ICE runs out of gas, I can use a gas can to add emergency fuel. What happens if the public charger I'm counting on is out of service or I fail to notice my charge is low and I'm too far from anyone's exterior power outlet when I shut down? Can I hack-charge my Model S?

I saw a YouTube video of a guy in Europe somewhere with a Leaf that had run dead. He had a buddy tow it with a rope while he gently pressed the brake (to engage re-gen) and it worked! I wish I could find the link again to post. Since Model S goes into re-gen when your foot comes off the gas, could you even dolly-tow it with the front wheels off the ground for a few miles with the can "on" and get some range back? (The thread is Hack-Charging, so I am just blue-skying here).

Dino Saver said:
And while I'm in survivalist mode, what happens if my Model S blows a tire? I have a spare in the trunk of my ICE. Aside from space, is there any reason not to carry a spare in one's S? I don't play golf or do the food shopping. I'm not sure what I need all that space for besides a spare.

I wonder about that too. My concern would be around jacking the car up. You'd want to be very sure of your lifiting points so as not to puncture the battery case or similar!

Doug_G · Aug 24, 2012

MikeK said:
This has been really informative. I was planning to buy a back-up generator for the house. Now I know to look for a Honda inverter generator!

Make sure you get a good quality one. Many inverter generators produce too much harmonics and the Roadster won't accept that either. It's a very fussy eater. I assume the Model S will be similarly picky.

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